Add disassembler tests for mips2 platform. There are no functional changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224252 91177308-0d34-0410-b5e6-96231b3b80d8
Add disassembler tests for mips3 platform. There are no functional changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224253 91177308-0d34-0410-b5e6-96231b3b80d8